Medicated patches that have antiinflammatory, analgesic or cooling effects are now widely used in the symptomatic treatment of lumbago, joint pain, shoulder stiffness and other symptoms caused by aging, hard work and other conditions.
Conventional medicated patches, including poultice-type patches, typically have a multilayer structure. As an example, a conventional medicated patch 10 is shown in FIG. 4. The medicated patch 10 has a multilayer structure including a white or skin-colored backing 20, an adhesive drug-containing matrix 30 that is spread substantially entirely over one surface of the backing, and a sheet of liner 40 that entirely covers the drug-containing matrix.
Certain medicated patches, such as medicated patch 10 shown in FIG. 5, include a tear line 50 at the middle of the liner 40. To apply this type of medicated patch, the user stretches the patch to tear the liner at the tear line and holds the exposed drug-containing matrix 30 against the application site for temporal tacking while peeling off the torn pieces of the liner, so as to finally apply the patch to the application site (See, for example, Patent Document 1).
These medicated patches have the following drawbacks regarding the removal of the liner upon application.
The common medicated patch 10 as shown in FIG. 4 requires the user to peel the liner 40 by rubbing the edge of the medicated patch 10 with fingers, thus causing the liner 40 to partially come off. Many of the patients are aged people who have decreased dexterity and this rubbing and pealing is difficult and complicated for many of the aged people.
The medicated patch shown in FIG. 5 has been developed to facilitate the above-described process. However, tearing the liner 40 by forcibly stretching the medicated patch 10 from both right and left sides causes the patch to wrinkle. As a result, even if the user manages to peel the liner from both sides and apply the medicated patch to the application site, it is often necessary to remove the patch from the application site and reapply it after removing wrinkles. The reapplied patch often loses its initial stickiness and tends to come off during daily activities.
Furthermore, aged people are used to the conventional peeling method shown in FIG. 6 and therefore tend to peel the liner 40 by rubbing the edge of the medicated patch 10. In many cases, this will lead to the liner being torn along the tear line 50, forcing the user to repeat the process of rubbing the edge of the remaining film to peel it. Even if the liner contains a clearly visible instruction on how to peel the film, such instructions are neglected by most of the patients.
Some medicated patches have been proposed to address these problems. In one such medicated patch, the liner attached to the drug-containing matrix consists of two separate films. The edge of one film is folded upward along the mid-portion of the drug-containing matrix and the other film is overlaid on top of the fold of the first film. This construction assists the user in peeling the liner (See, for example, Patent Documents 2 and 3).
In another medicated patch, one side of the backing is not coated with the drug-containing matrix. In still another medicated patch, one corner of the backing and the drug-containing matrix is cut so that part of the protective sheet is exposed (See, for example, Patent Documents 4 and 5).
However, the medicated patch in which the drug-containing matrix is covered with two separate liners requires complex procedures to produce. In addition, the upward folding of the edge of one of the liners that is arranged below the other film cannot be effected uniformly.
The medicated patch in which one side of the backing is not coated with the drug-containing matrix tends to come off from the uncoated side during the application. The medicated patch in which one corner of the backing and the drug-containing matrix is cut to expose part of the protective sheet still presents difficulty to aged people trying to pinch the exposed part of the protective sheet since the exposed part is not large enough.    Patent Document 1: Japanese Laid-Open Patent Publication Hei 8-112305    Patent Document 2: Japanese Laid-Open Patent Publication 2000-219622    Patent Document 3: Japanese Laid-Open Patent Publication 2000-351717    Patent Document 4: Japanese Laid-Open Patent Publication 2000-175960    Patent Document 5: Japanese Laid-Open Patent Publication 2000-175961